1. Field of the Invention
This invention relates to a mobile drilling and bolting machine and more particularly to a drilling and bolting assembly mounted for transverse and longitudinal movement on a frame portion for precisely positioning the assembly to drill bolt holes and install roof bolts at preselected locations in a mine roof.
2. Description of the Prior Art
In underground mining, it is the conventional practice to support the mine roof by bolts that extend into predrilled holes in the mine roof and to secure bearing plates or horizontal timbers in abutting relation with the roof surface. The holes are drilled in rows that extend transversely and longitudinally of the entry in a selected pattern with the holes spaced at given intervals. Conventional, modern drilling machines such as disclosed in U.S. Pat. No. 3,252,525 and 3,375,880 teach progressively moving a drilling machine mounted on a mobile body portion through the mine and drilling bolt holes in the roof according to a standard bolt pattern. The drilling machine is carried on the end of a boom member which is raised and lowered in a linear vertical path to permit vertical drilling of bolt holes in the roof. In addition, the boom through a horizontal linkage mechanism is operable to position the drill unit for drilling holes in the roof along a straight line transverse to the longitudinal axis of the drilling machine and across the entry. By selectively moving the boom, the bolt holes may be spaced at preselected intervals to provide the optimum roof support. When a transverse row of holes has been drilled, the operator either advances the drilling unit forwardly in a path parallel to the longitudinal axis of the drilling machine or forwardly advances the entire mobile machine a given distance ahead to drill a subsequent transverse row of holes.
Considerable effort and skill is required on the part of the machine operator to locate the drill for drilling holes in the mine roof that conform to a selected pattern. Not only must the operator be concerned with maintaining the correct spacing between adjacent holes in the transverse row, but also with maintaining proper spacing between adjacent longitudinal rows whereby the holes are spaced both transversely and longitudinally at given intervals according to the selected pattern. Subsequently, considerable delay is encountered in locating the holes for drilling, especially if the longitudinal spacings between transverse rows is accomplished by forward tramming of the drilling machine. Because the roof drilling and bolt installation operation is the slowest operation in the mining cycle, it is essential these operations be conducted without unnecessary delays in locating and drilling the bolt holes.
The conventionally known roof bolting machines require that the operator work under exposed portions of the mine roof, subjecting the operator to the hazard of rock material dislodging from the roof during the drilling and bolting operations. To reduce the hazard, temporary roof jacks, which are manually set in placed by the operator, have been utilized to support the section of roof into which the holes are to be drilled. However, considerable time is involved engaging and disengaging the temporary jacks resulting in additional delay of the mining cycle.
There is a need for a mobile drilling and bolting machine that drills bolt holes and installs roof bolts in the roof of an underground mine in which the roof drill is selectively moved to drill holes in the mine roof in transverse and longitudinal rows at spaced intervals with the operator protected at all times from the hazard of roof falls.